The Oscar-winning pop star also revealed that she and the charitable organisation Global Citizen have already raised $35m (£28m) for the World Health Organisation.
Gaga’s event, which she has helped organise with Global Citizen, is called the One World: Together at Home concert, and will see stars performing from their homes. Money raised by the event will support the COVID-19 Response Fund, powered by the UN Foundation, which will globally fund essential PPE, supplies and testing kits.
The event will be streamed across the internet, including YouTube, Twitter and Facebook, on 18 April. A highlights show will be broadcast on BBC One on 19 April.
Artists to participate in One World will include Gaga herself, along with Paul McCartney, Billie Eilish, Elton John, John Legend, Chris Martin, Andrea Bocelli and Lizzo.
Also expected to appear are Maluma, Kacey Musgraves, Alanis Morissette, Billie Joe Armstrong, J Balvin, Burna Boy, Stevie Wonder, Eddie Vedder and Keith Urban.
Appearing in a non-musical capacity will be stars including David Beckham, Kerry Washington and Idris Elba, who last month revealed he had tested positive for coronavirus.
In a video announcing the event, Gaga expressed thanks to those on the front line.
“We are all so very grateful to all of the healthcare professionals across the country and around the world,” Gaga said. “What you are doing is putting yourself in harm’s way to help the world, and we all salute you.”
She continued: “It has been an honour to help with this huge broadcast event, where we need to tell the stories and celebrate the front line community, health care workers and their acts of kindness.
“We celebrate and highlight the singular, kind global community that is arising right now. We want to celebrate and encourage the power of the human spirit.”